Housing benefit changes: Campbell Robb and Jake Berry

Chief executive Campbell Robb said some "spare" bedrooms were in fact used by disabled people for their wheelchairs and storage, or for children of divorced parents staying over, and said some people had to cope with "very special circumstances".

Conservative MP Jake Berry, an aide to Conservative Party Chairman Grant Shapps, said it showed "the housing crisis we have in our country" which dates back 20 years, and was made worse by a lack of new social houses.

He said there were one million spare bedrooms in the UK, costing the taxpayer £0.5bn a year that were not being used, and he said: "This is about fairness".

They were debating changes which the government calls a "single-room subsidy" but Labour has dubbed a "bedroom tax".